OregonFlora: Juncus exiguus

	Juncus exiguus
	Klamath rush, weak rush
Habit	Plants perennial, 40–90 cm tall, cespitose, fresh stems shiny (dull), green, smooth (with relatively inconspicuous ridges); dried fruiting stems slender, 0.7–1.5 mm diameter above distal sheath, often turning blue-green with 6–11(13) strong low ridges per side becoming visible; dried ridges coarse or wide, capped with low dull cells.
Leaves	lacking blades; proximal sheaths smooth (at 10×); distal sheaths 3–14 cm; distal half green to pale brown; thin; dull, not papillose; nerves prominent; apices symmetrical, unwinged; thin; dark and often slightly inrolled towards stem.
Inflorescences	loose clusters; branches visible; inflorescence bracts not swollen; erect in fruit.
Flowers	tepals 6, usually mid to dark brown-striped; stamens 3; filaments 0.3–0.8 mm; anthers (0.3)0.4–0.8(0.9) mm; styles 0.2–0.3 mm.
Capsules	2.2–3 mm; shorter than or equaling the tepals; light to dark brown, 1-chambered.
Seeds	0.35–0.5 × 0.2–0.25 mm, reticulate, apiculate.

	Juncus exiguus
Distribution	[BONAP county map]
Discussion	Shores, wet meadows, marshes, stream banks, springs, peatlands. 900–2300m. CR, Sisk, Casc. CA; southeast to AZ. Native. The fresh upper stems of this species are variable, but are often smooth, green, and shiny. Upon drying they become blue-green and clearly ridged, so the plants look quite different in the field and in a herbarium. Similar Juncus hesperius is found at lower elevations and has papillose proximal sheaths; J. exiguus is montane and is never papillose.
Source	Flora of Oregon, volume 1, page 277 Peter Zika
Sibling taxa	J. acuminatus, J. anthelatus, J. articulatus, J. balticus, J. bolanderi, J. brevicaudatus, J. breweri, J. bryoides, J. bufonius, J. bulbosus, J. canadensis, J. capillaris, J. capitatus, J. compressus, J. confusus, J. conglomeratus, J. covillei, J. diffusissimus, J. drummondii, J. dudleyi, J. effusus, J. ensifolius, J. ensifolius x Juncus nevadensis, J. falcatus, J. filiformis, J. gerardi, J. hemiendytus, J. hesperius, J. howellii, J. inflexus, J. interior, J. kelloggii, J. laccatus, J. lescurii, J. longistylis, J. marginatus, J. mertensianus, J. mexicanus, J. nevadensis, J. occidentalis, J. orthophyllus, J. oxymeris, J. parryi, J. patens, J. pelocarpus, J. planifolius, J. ranarius, J. regelii, J. saximontanus, J. supiniformis, J. tenuis, J. tiehmii, J. torreyi, J. triglumis, J. trilocularis, J. uncialis
Synonyms	Juncus effusus var. exiguus
Web links	Local floras: CA, OR Local Web sites: CalFlora, CalPhotos, Flora NW, PNW Herbaria WildflowerSearch iNaturalist (observations) LBJ Wildflower Center SEINet Plants of the World Online Encyclopedia of Life Wikipedia Google Image Search

Juncus exiguus

Klamath rush, weak rush

Habit

Plants perennial, 40–90 cm tall, cespitose, fresh stems shiny (dull), green, smooth (with relatively inconspicuous ridges); dried fruiting stems slender, 0.7–1.5 mm diameter above distal sheath, often turning blue-green with 6–11(13) strong low ridges per side becoming visible; dried ridges coarse or wide, capped with low dull cells.

Leaves

lacking blades;

proximal sheaths smooth (at 10×);

distal sheaths 3–14 cm;

distal half green to pale brown; thin; dull, not papillose; nerves prominent;

apices symmetrical, unwinged; thin; dark and often slightly inrolled towards stem.

Inflorescences

loose clusters;

branches visible;

inflorescence bracts not swollen; erect in fruit.

Flowers

tepals 6, usually mid to dark brown-striped;

stamens 3;

filaments 0.3–0.8 mm;

anthers (0.3)0.4–0.8(0.9) mm;

styles 0.2–0.3 mm.

Capsules

2.2–3 mm; shorter than or equaling the tepals; light to dark brown, 1-chambered.

Seeds

0.35–0.5 × 0.2–0.25 mm, reticulate, apiculate.

Juncus exiguus

Distribution

[BONAP county map]

Discussion

Shores, wet meadows, marshes, stream banks, springs, peatlands. 900–2300m. CR, Sisk, Casc. CA; southeast to AZ. Native.

The fresh upper stems of this species are variable, but are often smooth, green, and shiny. Upon drying they become blue-green and clearly ridged, so the plants look quite different in the field and in a herbarium. Similar Juncus hesperius is found at lower elevations and has papillose proximal sheaths; J. exiguus is montane and is never papillose.

Source

Flora of Oregon, volume 1, page 277
Peter Zika

Sibling taxa

J. acuminatus, J. anthelatus, J. articulatus, J. balticus, J. bolanderi, J. brevicaudatus, J. breweri, J. bryoides, J. bufonius, J. bulbosus, J. canadensis, J. capillaris, J. capitatus, J. compressus, J. confusus, J. conglomeratus, J. covillei, J. diffusissimus, J. drummondii, J. dudleyi, J. effusus, J. ensifolius, J. ensifolius x Juncus nevadensis, J. falcatus, J. filiformis, J. gerardi, J. hemiendytus, J. hesperius, J. howellii, J. inflexus, J. interior, J. kelloggii, J. laccatus, J. lescurii, J. longistylis, J. marginatus, J. mertensianus, J. mexicanus, J. nevadensis, J. occidentalis, J. orthophyllus, J. oxymeris, J. parryi, J. patens, J. pelocarpus, J. planifolius, J. ranarius, J. regelii, J. saximontanus, J. supiniformis, J. tenuis, J. tiehmii, J. torreyi, J. triglumis, J. trilocularis, J. uncialis

Synonyms

Juncus effusus var. exiguus

Web links

Local floras: CA, OR
Local Web sites: CalFlora, CalPhotos, Flora NW, PNW Herbaria
WildflowerSearch
iNaturalist (observations)
LBJ Wildflower Center
SEINet
Plants of the World Online
Encyclopedia of Life
Wikipedia
Google Image Search

Unless otherwise noted, all data comes from OregonFlora.

Choose a data source: OregonFlora

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Juncus exiguus

Juncus exiguus